For that purpose an integer called a backshell has been provided. In one way or another this bridges over the male and female members of the coupling so that any tension on the optic lead or leads is not transferred to the joint between those members.
The present construction is intended to deal with one or more problems of particular relevance to optic fiber technology--the need to avoid twisting, tension is on the fragile optic fiber and sharp deviations in the fibers.